HOMEBREW Digest #4805 Wed 20 July 2005

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  FOY, 05- Oxygenation ("Rob Moline")
  FOY, 05-Mead-Schramm ("Rob Moline")
  Question about Dextine malt AND ROD's TRAVELS ("Rod Prather")
  FOY (2005): dry yeast/liquid yeast ("Peter A. Ensminger")
  David Edge:  Vital Dyes ("Shawn E. Lupold, Ph.D.")
  Fortnight Of Yeast, 2005 (Matt)
  Special B ("Rob Moline")

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * The HBD Logo Store is now open! * * http://www.hbd.org/store.html * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Suppport this service: http://hbd.org/donate.shtml * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Beer is our obsession and we're late for therapy! * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Fortnight of Yeast 2005 - 10 July through 24 July * * Presented in cooperation with Lallemand * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Send articles for __publication_only__ to post@hbd.org If your e-mail account is being deleted, please unsubscribe first!! To SUBSCRIBE or UNSUBSCRIBE send an e-mail message with the word "subscribe" or "unsubscribe" to request@hbd.org FROM THE E-MAIL ACCOUNT YOU WISH TO HAVE SUBSCRIBED OR UNSUBSCRIBED!!!** IF YOU HAVE SPAM-PROOFED your e-mail address, you cannot subscribe to the digest as we cannot reach you. We will not correct your address for the automation - that's your job. HAVING TROUBLE posting, subscribing or unsusubscribing? See the HBD FAQ at http://hbd.org. LOOKING TO BUY OR SELL USED EQUIPMENT? Please do not post about it here. Go instead to http://homebrewfleamarket.com and post a free ad there. The HBD is a copyrighted document. The compilation is copyright HBD.ORG. Individual postings are copyright by their authors. ASK before reproducing and you'll rarely have trouble. Digest content cannot be reproduced by any means for sale or profit. More information is available by sending the word "info" to req@hbd.org or read the HBD FAQ at http://hbd.org. JANITORs on duty: Pat Babcock (pbabcock at hbd dot org), Jason Henning, and Spencer Thomas
---------------------------------------------------------------------- Date: Tue, 19 Jul 2005 22:05:16 -0500 From: "Rob Moline" <jethrogump at mchsi.com> Subject: FOY, 05- Oxygenation Subject: Fortnight Of Yeast, 2005 From: Matt <baumssl27 at yahoo.com> Question: Can you please comment on the strategy of trying to aerate/oxygenate the yeast while they are in a STARTER rather than aerating the wort itself. (Please let me abuse the language and science a bit and just say that yeast need "a big swallow of oxygen" before they ferment beer.) I understand that this is exactly your strategy in the production of dry yeast--i.e. dry yeast can be pitched into unaerated wort because they have already taken their big swallow of oxygen. How feasible is it for a homebrewer to grow up a starter in similar fashion? Is continuous aeration of the starter required? A stir plate? If I have no stir plate, and no gas transfer equipment of any kind, is there a practical procedure I can follow to grow yeast whose oxygen requirements are already met? Letting air into the starter jug and shaking it, repeating this over several days, etc? Any temperature dependency? Any minerals or nutrients I can add to the starter to increase the yeast's efficiency at storing up oxygen-related compounds? Thank you for sharing your expertise. Clayton: Yeast need a trace amount of oxygen in an anaerobic fermentation such as brewing to produce lipids in the cell wall. With out O2 the cell cannot metabolize the squalene to the next step which is a lipid. The lipids make the cell wall elastic and fluid. This allows the mother cell to produce babies, buds, in the early part of the fermentation and keeps the cell wall fluid as the alcohol level increases. With out lipids the cell wall becomes leathery and prevents bud from being formed at the beginning of the fermentation and slows down the sugar from transporting into the cell and prevents the alcohol from transporting out of the cell near the end of the fermentation. The alcohol level builds up inside the cell and becomes toxic then deadly. Lallemand packs the maximum amount of lipids into the cell wall that is possible during the aerobic production of the yeast at the factory. When you inoculate this yeast into a starter or into the ferm, the yeast can double about three time before it runs out of lipids and the growth will stop. There is about 5% lipids in the dry yeast. At each doubling it will split the lipids with out making more lipids (no O2). The first split leaves 2.5% for each daughter cell. The second split leaves 1.25% for each daughter cell. The next split leaves 0.63%. This is the low level that stops yeast multiplication. Unless you add O2 the reproduction will stop. When you produce 3-5% alcohol beer this is no problem. It is when you produce higher alcohol beer or inoculate at a lower rate, that you need to add O2 to produce more yeast and for alcohol tolerance near the end of fermentation. You definitely need added O2 when you reuse the yeast for the next inoculum. If you prepare a starter culture you will need added O2. in the starter and perhaps in the main mash as a precaution. You will need to follow the precautions as mentioned above. If the mash is designed to produce 3-5% alcohol you may not need added O2. Brewing above that needs added O2. Regarding you comment about growing your own yeast that will not need added O2 in the fermenter; The Lallemand yeast factory grows yeast under a different metabolic pathway than you will have in your starter culture. We feed the media to the aerobic fermentation at a rate that will keep the sugar levels below 0.2% at all times to maintain the Pasteur Effect. This builds cell mass with minimum to no alcohol production. As the sugar level rises above 0.2% the Crabtree Effect begins and no matter how much air you feed the fermentation, alcohol + CO2 are the main by-products. Your starter culture will have a much higher level of sugar. You will produce some cell mass but mostly alcohol and CO2 no matter how much air you add by stirrer or bubbles. I will bow to Dr. Tobias to reply regarding the preparing a starter yeast with enough O2 to inoculate without further aeration. Tobias routinely prepares starter cultures for his research projects. Clayton Cone - -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.323 / Virus Database: 267.9.2/52 - Release Date: 7/19/2005 Return to table of contents
Date: Tue, 19 Jul 2005 23:47:17 -0500 From: "Rob Moline" <jethrogump at mchsi.com> Subject: FOY, 05-Mead-Schramm Ken/Jean Schramm <schramk at mail.resa.net> Subject: Fortnight of Yeast: Rob; My questions revolve around mead fermentation. Q's for the panel: What is the ideal timing for nutrient additions for mead fermentations? Clayton: Yeast prefer that the nutrients be added in increments over the first 1/3 of the fermentation. When all of the nutrients are added only at the beginning a large cell mass is produced with each cell having a low protein content. This low protein content makes it difficult to complete the fermentation and withstand the alcohol toxicity near the end. Adding the nutrients, primarily Nitrogen, in encrements results in less, but adequate, yeast growth with each cell having a larger amount of protein. High protein yeast ferment faster and with stand alcohol toxicity better than low protein yeast. Yeast sugar transport systems that bring the sugar into the cell at a prescribed rate, contain nitrogen. Some of their half life span is about two hours, so new transport enzymes must be generated constantly. This requires a fresh source of available nitrogen. Yeast require a steady source of nitrogen through out the growth phase to produce DNA, RNA, amino acids, proteins and other cell components. If the sulfur containing amino acid skeleton is not available to receive the H2S as the yeast produces it, the yeast will expel it out of the cell resulting in rotten egg odor. Just as a point of interest, yeast produce 30+ times as much alcohol in he growth phase as it does in the stationary phase. So be nice to the yeast while it is growingand keep it growing as long as possible. How do deficiencies of specific amino acids of wine and mead musts contribute to the production of higher alcohols? The two approaches to their production I have seen in print are oxidative deamination and the carbohydrate route. Could you provide some input on which one is correct, and how it proceeds? Clayton: Both routes are used by the yeast. 1.In a amino acid rich or sufficient environment, the yeast takes the catabolic or Ehrlich route to strip the amino acid of its NH3 to use for its own building blocks. The remainder of the amino acid produces a one carbon less higher alcohol. 2. In an amino acid deficiency environment, the yeast will use the anabolic biosynthesis route and produce the alpha-keto acid from glucose then on to a higher alcohol. Example: Catabolic or Ehrlich route -- Valine to alpha-keto acid to Isobutanol. Anabolic route --- glucose to alpha keto acid to Isobutanol. The above are over simplifications of what really takes place and brings into question the exact Ehrlich pathway. The four higher alcohols that I have seen presented that account for off flavors in beer and wine are n-propanol, isoamyl alcohol, active amyl alcohol, and isobutanol. Are these the culprits in mead? Clayton: The four higher alcohols that you mentioned are present in all fermented beverages and are an important part of their flavor and aroma profile. A full bodied ale can handle more than a lager. A rich red wine requires and perhaps masks more than a light white wine. A metheglin requires more of these alcohols than traditional mead before they become an off flavor. The secret is having them there in the right amount. Do you feel it is possible to conduct a .100 point SG fermentation of mead must with a FAN content of 20-40 ppm and no nutrient addition without the production of off flavors and higher alcohols? Which yeast strains might favor nutrient free fermentations, if any? (I am not a believer in this option, but I am asking on behalf of some I know who are.) Clayton: I wish that I had a good answer for you from actual experimental data but I don't. .100 SG is about 26% sugar. This alone would require additional yeast and nutrients to complete the fermentation. Before nutrients requirements were understood and added, mead makers were satisfied to have fermentations that lasted 6 to 18 months. If I had to make a guess as to what strain of yeast might work under those conditions I would try Uvaferm 43 or Lalvin EC-1118. Both tend to be neutral in ester formation and have low Nitrogen requirements and are strong fermenters. I would try it on a very small amount. Double the amount of yeast inoculum and rehydrate the yeast in the presence of Go-Ferm. Give it plenty of air the first 72 hours and watch the pH during the first 12 to 24 hours. Do not let the pH drop below 3.0. Add potassium carbonate if necessary. Let me know your results. Thanks, Ken Schramm - -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.323 / Virus Database: 267.9.2/52 - Release Date: 7/19/2005 Return to table of contents
Date: Tue, 19 Jul 2005 21:58:29 -0700 From: "Rod Prather" <rodpr at comcast.net> Subject: Question about Dextine malt AND ROD's TRAVELS Could someone explain the purpose of Dextrine Malt in a grain bill? ROD's TRAVELS. Recent Impressive Beers. Unibroue Ephemere9 , Carolus Grand Cru9, Widmer's Wheat.8 Chechvar 8(Very nice pils, Budweiser it isn't) Recent Brew Pubs. BJ's. Ontario Ca. Rising corporate brewpup chain. Great atmosphere, Damned good beers. Had a 7 glass tester. The Kolsch is OK but it's not a real Kolsch, no lagering and a bit of aldehyde. The Wheat was quite nice but a bit restrained. Their almost perfect Pale Ale and the refreshing 5 grain Amber Ale are both delights. The Stout is confusing. You are lead to believe it is a Russian but it seems to be a compromise between an Irish, Russian and a Sweet Stout. Slightly sweet with a distinct mouthfeel. None of the lightness I expect from Russian Stout. Overall, a very nice range of beers. Each of their beers are distiguishable and have distincive flavors and hoppings make their tester a great time. . OH! The food looked good, too. Return to table of contents
Date: Wed, 20 Jul 2005 01:00:51 -0400 From: "Peter A. Ensminger" <ensmingr at twcny.rr.com> Subject: FOY (2005): dry yeast/liquid yeast FOY: 2005: Question: For a homebrewer, dry yeast is much more convenient than liquid yeast. There are numerous strains of dry brewer's yeast that give very nice results for certain beer styles. However, the variety of dry brewer's yeast seems very limited. I would like to see dry satchels of yeast for making German Weizenbier (like Wyeast 3068), Belgian beers (like Wyeast 1214 etc), and a better selection of dry yeasts for lagers. Can we expect to see a better selection of dry yeasts in the future? What are the technical problems that prevent development of a greater variety of dry brewer's yeast? Sincerely, Peter A. Ensminger Syracuse, NY Return to table of contents
Date: Wed, 20 Jul 2005 09:22:27 -0400 From: "Shawn E. Lupold, Ph.D." <slupold at jhmi.edu> Subject: David Edge: Vital Dyes David Edge wrote about Methylene Blue staining for yeast viability. We regularly use these techniques in mammalian cell culture. We use Trypan Blue, which is cheap and can be bought pre-mixed by credit card from most lab supply companies (try InVitrogen ($11/100ml) or Sigma-Aldrich). Buy the pre-mixed stuff...unless you want to turn your house blue. In the lab, I've used it for up to a year. When it gets old the blue dye congregates and gives a "speckled" background, but it still sufficiently differentiates live from dead. 100 mls should last you a long, long time. I've never tried it on my yeast though. I quickly look in the microscope to ensure there is no bacterial contamination and to roughly gauge health/viability by morphology (i.e.- shape and presence of budding). Shawn Return to table of contents
Date: Wed, 20 Jul 2005 09:03:47 -0700 (PDT) From: Matt <baumssl27 at yahoo.com> Subject: Fortnight Of Yeast, 2005 In today's response on the question of whether there are more or less "beer yeasts" these days, Dr. Cone mentioned that many yeasts currently considered to be "wine yeasts" may produce excellent beer. In his book "Farmhouse Ales," Phil Markowski reports that it is speculated that the primary Dupont strain descends from red wine yeast. He also reports that fermentation at Dupont is similar to red wine fermentation in many ways (temperature, duration, philosophy). So experimenting with wine yeasts is something I've been thinking about a bit. Can you elaborate on this? Are there specific strains marketed by your company that would be good candidates for experimentation? Are there any "red flags" or "green lights" that one should look for in commercial descriptions of wine yeasts, when trying to identify strains for experimenting? Is it likely that most wine yeasts will lead to estery, Belgian-style flavors? Finally, are there specific wine yeasts you know of that give brettanomyces-like leathery flavors, but in a more controlled or predictable way than a pure brett culture would? I greatly appreciate any guidance you can give. Thanks, Matt Return to table of contents
Date: Wed, 20 Jul 2005 21:24:36 -0500 From: "Rob Moline" <jethrogump at mchsi.com> Subject: Special B From: "BILL KUNKA" <wkunka at vianet.ca> Subject: Subsitution for Special B malt? Special B is malted by Dingemans, distributed by Cargill. http://www.specialtymalts.com/dingemans/descriptions.html Cheers! Gump "The More I Know About Beer, The More I Realize I Need To Know More About Beer!" - -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.323 / Virus Database: 267.9.2/52 - Release Date: 7/19/2005 Return to table of contents
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